Muscle Innervation

To more closely examine how the moth Manduca sexta generates the turning maneuvers which make up the zigzagging turning pattern, we study how the nervous system activates the muscles involved with flight. Most recently we have begun to examine the central nervous system control of the muscles underlying abdominal ruddering during tethered flight. We use fine wire electrodes to record which thoracic and abdominal muscles the moth uses while turning left or right during tethered flight and how the muscle activity between the thorax and abdomen are coordinated during attempted turning.

We have found that during straight forward flight the left and right abdominal dorsal longitudinal muscles (DLM 1, right and left shown above) are activated in phase with each other and out of phase with the thoracic DLMs which cause the depression of the wings during flight. During turns the abdominal DLMs are activated out of phase with each other possibly causing asymmetrical movements. Another part of the abdominal DLM muscle, called DLM 2, appears to be involved in posture and abdominal ruddering.